class T3E01 
{
	public static Shape randShape()
	{
		switch ((int)(Math.random()*3))
		{
		default: //注意必须放在最前面
		case 0:  
			return new Circle();
		case 1:  
			return new Square();
		case 2: 
			return new Triangle();
		}
	}
	public static void main(String[] args) 
	{
		Shape[] s = new Shape[9];
		for(int i = 0; i< s.length; i++)
			s[i] = randShape();
		for(int i = 0; i < s.length; i++)
			s[i].draw();
	}
}


class Shape 
{ 
  void draw() {}
  void erase() {} 
}

class Circle extends Shape 
{
	void draw()
	{
		System.out.println("Circle.draw()");
	}
	void erase()
	{
		System.out.println("Circle.erase()");
	}
}

class Square extends Shape
{
	void draw()
	{
		System.out.println("Square.draw()");
	}
	void erase()
	{
		System.out.println("Square.erase()");
	}
}
class Triangle extends Shape
{
	void draw()
	{
		System.out.println("Triangle.draw()");
	}
	void erase()
	{
		System.out.println("Triangle.erase()");
	}
}